Study On The Collector-distributor Road In The Interchanges On Freeway

Interchange is an essential part. of freeway, whose form is various and complicated. Interchange is important hub and node of freeway, which plays an important role in vehicles running on freeway. the setting problem of collector-distributor road in the scope of interchanges on freeway, such as cloverleaf, cotyledons interchange, etc.. The issues that which connection form is adopted between two annular ramp, how much turn traffic volume the distance can adapt need to be resolved. When the distance is too long, it will cause the expansion of the scale of interchange, thus make cost increased. If the distance is too short, and traffic volume is too big, it is bad to the traffic safety, especially for high-speed vehicles on freeway, traffic accidents probability will rise. Meanwhile, the type of interchange is also very important, we should avoid using this type which is bad to the traffic safety if conditions are allowed. So, for interchanges existing vehicles interwoven operation, it is very necessary to safety that the collector-distributor road is adopted or not and bow many lanes are needed.The paper discusses the influence factors of collector-distributor road, including interwoven length, traffic volume, traffic signs and the connection type between ramp and main road, etc.; If the index is not quantified, give on language description; Other conditions adopted interwoven area theory to calculate. The proposed distributed lanes set up to comprehensively consider all the factorsFor additional lane interwoven area, use the calculation method of the service level of interwoven area in "Highway capacity manual", on the conditions of highway and interwoven area secondary service level and ramp 3 service level, inverse calculation to maximum turn traffic volume interweave area length adapts, as the setting condition of collector-distributor road, use the same method,we can get the setting condition of two lane collector-distributor road; According to set conditions of collector-distributor road we get, use VISIIM traffic simulation software to simulate and analyze, statistics traffic conflict number of vehicles in interwoven area, choose proper evaluation for safety transportation evaluation, then check the correctness of set conditions of collector-distributor road we get.My research provides a strong theoretical guidance for interchanges existing vehicles interweaves run, and reference to set conditions of collector-distributor road. Meanwhile, it offers methods and ideas for the existing code of interchange about collector-distributor road, and convenience to designer, which has certain practical significance.